328 EESPIEATION 



dioxide for oxygen. The purifying or removal of wastes 

 from the blood is performed by an entirely different set 

 of organs, which we shaU consider more in detail in a 

 following chapter. 



The whole respiratory system, then, is simply a device for 

 getting the blood into thin walled tubes and these tubes 

 in contact with air, in order that the process of osmosis 

 may bring about the exchange of the two gases, oxygen 

 and carbon dioxide. 



Breathing Habits. 



Costal and abdominal breathing. — In man, in quiet, 

 normal breathing, the operation is mainly confined to dia- 

 phragm movement, the ribs expanding very little. In 

 woman, on the contrary, quiet breathing is carried on 

 mainly by the rib movements. These two kinds of breath- 

 ing are spoken of usually as abdominal (diaphragm) and 

 costal (rib) breathing. It is not believed that the two 

 kinds are to be associated primarily with the sex, but, on 

 the contrary, it is believed that the costal method of the 

 woman has resulted from the tightness of her clothing as 

 compared with that of a man. The use of corsets and 

 tight fitting dress waists tends to restrict the expansion of 

 the abdomen, and forces the use of the upper ribs for the 

 purpose. If such tight dressing is carried to excess, as in 

 tight lacing, not only is abdominal breathing prevented, 

 but even rib action is interfered with, and thus the entire 

 breathing action or chest cavity enlargement may be inter- 

 fered with. Such interference results in insufficient air 

 supply to the lungs and body tissues, and the distorting of 

 the skeleton, and subjects the abdominal organs to such 



